gmp-devel Digest, Vol 1, Issue 89

[Paul Zimmermann]

   By the way, I think I've understood how to do binary gcdext (although
   in the context of Schönhage's algorithm, I can use that only for the
   one limb basecase): [...]

There is a binary gcdext described in the book of Crandall/Pomerance
[Algorithm 9.4.3, pages 426-427], although I did not try to implement it.

Paul